Internal-combustion engine



INTERNAL coNBusTIoN" ENGINE Filed Aug. 1926 5g Z lZL .EIL. 21 v iWITNESSES 1 17: 6-5

Patented Sept. 23, 1930 UNITED STATES PATENT OFFICE ROYAL LEE, OFMILWAUKEE, WISCONSIN, ASSIGNOR TO LEE ENGINEERING RESEARCH CORPORATION,OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN INTERNAL-COMBUSTIONENGINE Application filed August 4, 1928. Serial No. 127,Q40.

The invention relates to internal combustion engines, more particularlyof the twostroke-cycle type.

An object of the invention is to provide a two-stroke-cycle engineincluding charge precompression means of a-character permitting smoothoperation of the engine over a wide range of speed and load.

Another object of the invention is to provide-an engine in which apiston forms a bypass for the pre-compressed charge.

A further object of the invention is to rovide an engine in whichrelatively high ase pre-compression can be attained without danger ofleakage, thereby affording greater speed and torque range and good fuelecon- A further object is to provide an engine including by-pass meanswhich will permit variable base pre-compression in accordance with theengine speed and load.

A further object of the invention is to provide an engine including apressure-responsive inlet valve sensitive in action and quiet inoperation. I

The invention further consists in the several features hereinafter setforth and more particularly defined in the annexed claims.

In the accompanying drawings, Fig. 1 is a longitudinal sectionalelevation of an engine embodying the invention;

Fig. 2 is a transverse sectional view thereof taken onthe line 22 ofFig. 1: r

Fig. 3 is a detail sectional view of the base pie-compression means;

forming valve seats hereinafter described.

The cylinders 10 and 11 are in communication at their outer ends to forma common combustion chamber 14 into'which projectsa spark plug 15 orother ignition device, in the case of operation on carbureted or gaseousfuel. The cylinders 10 and 11 are preferably divided in a plane midwaybetween them and secured laterally together by bolts 16.

A pair of pistons 17 and 18, mounted for reciprocation in the cylinders10 and 11, respectively, are connected by a common piston pin 19extending between their intermediate portions and throu h slots 20 inthe adjacent cylinder Walls. crank shaft 21 is journalled in the crankcase 12 and is operatively connected to the piston pin 19 by aconnecting rod 22 disposed between the cylinders. The outer end of theconnecting rod ma project into the slots 20 in the cylinder wa ls inorder to obtain a good bearing on the piston pin. This disposition ofthe connecting rod in the slots is readily obtained by reason 'of thelateral assembly of the cylinders, which also avoids the necessity forthe usual piston pin plugs in the cylinders.

In accordance with well known practice, the pistons 17 and 18 aremovable simultaneously outwardly on a compression stroke andsimultaneously inwardly on an explosion or power stroke, at theconclusion of which a pre-compressed charge is admitted into onecylinder and blows through the common combustion chamber into the othercylinder, driving the spent gases before it. In the present instance,the spent gases are exhausted through ports 23 in the cylinder 11, theports being uncovered by the piston 18 near the end of the explosionstroke. For effecting precompression of the charge, it is convenient touse the pistons 17 and 18 acting on their inward stroke, which ingeneral, is also common practice. The present invention contemplates theimprovement of engines, preferably of the general type above described,to the end of securing a better engine operation over a wider range ofspeed and load.

In the present embodiment of the invention, the crank case 12 isprovided with a pair of shallow recesses 24 in axial alignment with thecylinders 10 and 11 and connected by a manifold 25 to a carburetor 26including a throttle valve 26. The carbureter is rovided in case ofoperation on carbureted uel, although the invention is not limited tosuch operation, as the fuel may be introduced by injection into thecylinders and only air sup plied to the recesses 24. The recesses 24 areclosed at their upper sides by the plate 13, which is provided aboveeach recess with sets of concentric arcuate o enings or ports 27 similarto those seen in t e valve seat of Fig. 4 hereinafter described. Theupper surface of the plate 13 is provided with annular grooves 28 inalignment with the arcuate openings 27 and annular grooves 29 betweenthe sets of arcuate openings, both sets of annular grooves serving-toincrease the effective area of the openings 27. The disposition of thesegrooves is similar to that shown in the valve seat of Fi 4 hereinafterdescribed. The upper surf ce of the plate 13 is ground to receive a pairof light disk valves 30 of thin metal, one above each recess 24. Eachdisk valve 30 is provided with annular sets of arcuate openings 31,which register with the annular grooves 29 formed between the arcuateopenings 27 of the plate 13. Each disk valve when seated on the plateeffectively closes the openings 27 with respect to pressure above thevalve. The disk valves 30 are each confined within a circularcounterbore 32 in the lower end of each cylinder 10 and 11, suchcounterbore serving to properly position the disk valve above theapertured plate 13 and to limit the upward movement or lift of thevalve.

The outward or upward movement of the pistons 17 and 18 isutilized todraw carbureted air from the recesses 24 into the lower ends of thecylinders, the disk valves 30 being lifted by the suction produced topermit the carbureted air' to flow through the openings 27 in the valveplate 13 and thence through the openings 31 in the valves. Following theexplosion or downward stroke of the pistons, it becomes necessary totransfer the charge in the lower ends of the cylinders to the upper endsof the cylinders, and this is accomplished in the present instance byadmitting the charge into the hollow interior of the pistons and thenceoutwardly from the upper end of piston 17. The lower or inner end ofeach piston 17 or' 18 is provided with a valve seat plate 33 secured tothe open end of the piston trunk by means of an inwardly flangedthreaded piston head 34. Each valve plate 33, as seen in detail in Figs.3 and 4, includes annular sets of arcuate openings or ports 35. Theupper surface of each valve plate is ground and provided with annulargrooves 36 in alignment with the arcuate openings 35 and annular grooves37 between the sets of arcuate openings, both sets of annular groovesserving to increase the effective area of openings 35. The ground uppersurface of each valve plate 33 receives a light disk valve 38 of thinmetal, the disk valve being provided with annular sets of arcuateopenings 39, which register with the annular grooves 37 formed betweenthe arcuate openings 35 of the valve plate. Each disk valve38 whenseated on the valve plate 33 efi'ectively closes the openings 35 withrespect to pressure above the valve. The valves 38 are each confined forlimited movement adjacent the valve seat by means of an annular spacingring 40 interposed between the valve seat and the edge of the pistontrunk.

The upper or outer end of piston 17 is provided w th anapertured valveseat plate 41 which may be identical with .the valve seat plate 33 andis secured to the end of the piston trunk by means of an inwardlyflanged piston head 42. An apertured disk valve 43, which may beidentical with the disk valve 38, is adapted to seat on the valve plate41 and is confined for limited movement by an annular spacing ring 44which permits the valve disk to open outwardly or upwardly when thepressure within the piston is greater than the pressure above thepiston. The pistons 17 and 18 are placed in communication by the pistonpin 19 which is hollow and is provided with ports 45 near its endsregistering with similar ports 46 in the pistons. Packing rings 47 arepreferably fitted into the piston pin on either side of the ports 45 inorder to avoid leakage from the space within the pistons.

In 0 eration, the simultaneous outward or upwar movement of the pistons17 and 18 creates a partial vacuum in the lower ends of the cylinderswhich causes the disk valves 30 to lift and admit carbureted air fromthe recesses'24 through the openings 27 of the plate 13, and thencethrough the openings 31 of the valves. During this travel of the pistonsthe disk valves 38 in the lower ends of the pistons seat against theirrespective valve plates 33 to close the openings or ports 35 therein. Assoon as the pistons commence their simultaneous inward or downwardstroke, the disk valves 30 immediately drop intoseating engagement withthe plate 13 permitting compression of the trapped charge in the lowerends of the cylinders. When the pressure of the trapped charge exceedsthe pressure within the pistons, the disk valves 38 in the lower ends ofthe pistons are caused to open, thereby forcing the charge into thepiston interior as the pistons move downwardly. The clearance at thelower ends of the pistons is made as small as possible in order toobtain good volumetric efiiciency and relatively high pre-compression.When the pressure of the charge within the pistons exceeds that in theupper ends of the cylinders, the disk valve 43 in the upper end of thepiston 17 is forced open and the compressed charge within the pistonsthereupon blows through the openings in the valve plate and disk valve43 and passes upwardly into cylinder 10, across the combustion chamber14 and downwardly into the upper end of cylinder 11. The charge forcedinto the upper end of the cylinders is then compressed charge is drawnin at the lower ends of the c linders in the manner above described.

en the pistons reach the upper ends of their travel ignition takes placeand the explosion of the charge causes the downward travel of thepistons on their working'stroke. When the piston 18 approaches itslowermost position, it uncovers the exhaust ports 23 thereby permittingthe spent gases to escape. As soon as the pressure of the remainingspent gases in the cylinders drops below the pressure of the freshcharge accumulated inthe pistons 17 and 18 the inlet disk valve 43 opensand the pro-compressed charge which is under considerable pressure blowsupwardly in the cylinder 10, through the common combustion chamber 14and downwardly into the upper end of the cylinder 11, driving the spentgases before it forcing them outof the exhaust ports 23. The disk valve43 is cooled to a safe temperature by the passage of the pre-compressedcharge through it.

In previous types of engines employing base or crank case compression,it has been customary to conduct the pro-compressed char e to thecombustion chamber by means I of a y-pass including ports in thecylinder walls uncovered b the piston in its travel.

With such types 0 engines it has been found impossible to employ a highdegree of precompression because of excessive leakage of the chargearound the piston and through the exhaustports or slots in the cylinderwalls, or both, as the case may be. This condition exists even with aproperly fitted piston and is aggravated after the piston has becomeworn in service. By eliminating the usual piston-controlled by-passports in the cylinder walls, it is possible to employ a relatively highdegree of charge pre-compression, since there is no danger of chargeleakage above noted. The relatively high charge pre-compression isaccomplished in the device of the .present invention by supplying aminimum clearance space for the pistons on their precompression stroke.

The amount of charge pre-compression is variable according to the enginespeed. and load, this being accomplished since the valve I meanscontrolling the pro-compression are pressure-responsive rather thanbeing controlled directly or indirectly by piston position. At smallthrottle openings of the carbureter the charge which accumulates in thepiston space is under somewhat less pressure than at full throttleopenings, thus permitting satisfactory operation at low speeds and underlight loads. With large throttle openings the pressure of the chargeaccumulating Within the istons reaches relatively high values, there ypermitting operation at high speeds with sustained torque because of thera id scavenging and full charging aflorded. he valve disks of theseveral valves are sensitive in action, as they are light and are notspring loaded. Theshort lift of these able, as they do not-affordsatisfactory operation at low speeds and light loads.

The pre-compressed charge issuing from the piston head forms ascavenging column occupying the entire diameter of the cylinder andpushing the spent gases bodily before it, thereby minimizing dilutionand providing good scavenging.

Under conditions of light load where the pre-compressed charge enteringthe cylinders does not reach the volume attained under normal loadconditions, the same action occurs as to cylinder 10 and any spent gasesthen remaining are confined to cylinder 11 and part of the combustionchamber 14, which preferably extends above the spark plug points toaccommodate the major portion of the compressed charge. The spark plug15, however, occupies a position over the cylinder 10 so that i itiontakes place in an undiluted portion o the charge, even when the amountof charge admitted to the cylinder is relatively small.

In order to retain the piston heads on the piston trunks againstrelative rotation each piston head is provided with an annular groove34* receiving therein a resilient ring 34 carrying an inwardlyprojecting locking pin 34, which extends through the piston head andinto the piston trunk, as seen in Fig. 3.

What I claim as new and desire to secure by Letters Patent is:

1. In an internal combustion engine, the combination of a cylinderincluding a combustion chamber,.a piston movable in said cylinder,iston-actuating means extending laterally rom said piston, chargepre-compression means including said piston, and chargepressure-responsive valve means at axially spaced portions of saidpiston permitting a pre-compressed charge to pass into said piston andfrom said piston into the combustion end of said 0 linder.

2. In an internal com ustion engine, the combination of a pair ofcylinders, pistons movable therein, charge pre-compression meansincluding said pistons, and a hollow piston pin connecting said pistonsand forming a conduit for the pre-compressed charge.

3. In an internal combustion en me, the combination of a pair of clinders aving a common combustion chamber, pistons movable in saidcylinders, charge pre-compression means including said pistons, a.hollow piston pin connecting said pistons and forming a conduit for thepre-compressed charge, and a pressure-responsive valve in one of saidpistons admittingithe charge to the combustion chamber of saidcylinders.

4. In an internal combustion engine, the combination of a pair ofparallel cylinders having adjacent aligned slots, pistons movable insaid cylinders, a piston pin connecting said pistons and projectingthrough said slots, and a connecting rod mounted on said piston pinbetween said cylinders to swing in a lane normal to the common axialplane of said cylinders and having its opposite ends projecting intosaid slots for reducing the overhang of said piston pin with respect tosaid connecting rod.

5. In an internal combustion engine, the combination of a cylinder, apiston movable I therein, an apertured valve plate secured to one end ofsaid cylinder, a charge-conducting member secured tosaid cylinder andhaving a recess in register with said valve 30 plate, acharge-pressure-responsive disk valve seated on said valve plate withinthe cylinder and movable off said plate to admit a charge within saidcylinder and movable into engagement with said plate to permitpre-compression of the charge by said piston, and by-pass means forconducting the precompressed charge to the opposite'end of saidcylinder.

6. In an internal combustion engine, the

combination of a cylinder, a piston movable therein and including aninwardly flanged piston head, an apertured valve plate secured withinsaid piston head, and a charge pressure-responsive disk valve movably'seated on said valve plate and having a plurality of ports therein forreceiving therethrough a pre-compressed charge.

7. In an internal combustion engine, the

combination of a cylinder, a piston movable therein and including aflanged member at its end, an apertured valve plate secured within saidflanged member, acharge pressureresponsive disk valve movably seated onsaid Valve plate and having a plurality of ports therein receivingtherethrough a compressed charge, and an annular spacing ring disposedabout said disk valve to provide lift clearance for said valve.

8. In an internal combustion engine,'the combination of a cylinder, apiston movable therein, a piston head having a threaded connection withsaid piston and having an an nular groove, a resilient ring disposed insaid groove, and a locking pin engaging said piston and piston head andretained against withdrawal by said resilient ring.

9. In an internal combustion engine, the combination of a cylinder, apiston movable therein, a piston head having a threaded connection withsaid piston and having an annular. groove, a resilient ring disposed insaid groove and having an lnwardly projecting member passing throughsaid piston therein, and valve means having a relatively large port areafor admitting into said cylinder an axially directed scavenging chargeoccupying substantially the entire area of the cylinder from the momentof its admiss1on. I

12. In an internal combustion engine, the combination of a cylinderhaving a combustion chamber, a piston movable in said cylinder andhaving a transverse sleeve portion provided with a port, a hollow pistonpin mounted in said sleeve portion and having a peripheral portregistering with the port in said sleeve portion to form a passage forthe flow of a charge'into said piston, and valve means in said pistonfor admitting the charge into said combustion chamber.

13. In an internal combustion engine, the combination of a pair ofcylinders having a common combustion chamber, pistons movable in saidcylinders and each having a transverse sleeve portion provided with a;port, charge pre-compression means, ahollow piston pin mounted in thetransverse sleeve portions of saidpistons and having ports registeringwith the ports in saidsleeve portions to form a passage for admittingthe pre-compressed charge from one PIS- ton to the other, and valvemeans in one of said pistons admitting the charge to said mg closed endportions, said piston pin having ports in its periphery registering withthe ports in said sleeve portions of the pistons to form a passage foradmitting the precompressed charge from one piston to the other, andvalve means in, one of said pistons admitting the charge to saidcombustion chamber.

15. In an internal combustion en 'ne, the combination of a pair ofcylinders aving a common combustion chamber, pistons movable in saidcylinders and each having a transverse sleeve portion'providedwith aport, charge pre-compression means, a hollow piston pin mounted in thetransverse sleeve portions of said pistons and having ports registeringwith the ports in said sleeve,portions to form a passage for admittingthe pre-compressed charge from one piston to the other,

and valve means in one of said pistons adioitting the charge to saidcombustion cham- 16. In an internal combustion engine, the combinationof a cylinder having a combustion chamber, a piston movable in saidcylinder, a piston head mounted on said piston and having an inturnedannular flange, a ported valve plate mounted between said inturnedflange and the end of the piston-and forming a valve seat on one face,an annular spacing ring also interposed between said inturned flange andthe end of the piston and bearing against the valve seat surface of saidvalve plate, and a ported valve disk disposed within said annular ringto be seated on said valve plate and having a limited lift from its seatdetermined by the thickness of said spacing ring.

17. In an internal combustion engine, the combination, with a'crankcase, of a pair of cylinder blocks secured to said crank case and eachhaving a cylinder bore therein forming part of a combustion space at oneend of the block opening laterally at the end of the block, attachingbolts securing said cylinder blocks in lateral engagement with thelaterally opening ends of said combustion spaces in registering relationto form a common combustion chamber for said cylinders, and a pairofpistons mounted in said respective said cylinder and piston beingarranged for relative movement, and a hollow support for said pistonextending laterally therefrom and forming a conduit for admitting acharge into said piston.

20. In an internal combustion engine, the combination of a pair ofcylinder blocks each having a cylinder bore therein, the cylinder boresin said blocks being arranged in parallel relation, attaching means forseparably securing said cylinder blocks laterally together, a pair ofpistons mounted in the respective bores of said cylinder blocks, andactuating means for effecting the simultaneous movement of said pistonsincluding a member laterally connecting said pistons.

21.. In an internal combustion engine, the combination of a pair oflaterally-adjacent cylinders each having a combustion chamber at one endand a pre-compression chamber at the other end, the combustion chambersof said cylinders bein in communication to form a common com ustionspace, a pair of hollow pistons mounted in said respective cylinders toreciprocate therein and each piston forming a reservoir for retainingtherein a pre-compressed charge, piston-actuating means connected tointermediate portions of said pistons, valve means for admitting acharge into said pre-compression chambers to be pre-compressed by saidpistons, valve means for admitting the pre-compressed charge into bothof said pistons and confining said charge within said pistons, and valvemeans for admitting the char e confined within said pistons into the comu'stion end of one of said cylinders.

In testimony whereof, I aflix m signature.

ROY LEE.

cylinder blocks'and connected for simultaneous movement.

. 18. In an internal combustion engine, the combination of a cylinderincluding a combustion chamber, a hollow trunk piston movable therein, aconnecting rod exterior to said cylinder, a piston pin having anoperative connection with saidconnectmg rod and mounted in anintermediate portion of the piston, charge pre-compression means, andcharge-pressure-responsive valve means disposed at opposite endportionsof said piston for admitting a pre-compressed charge into saidpiston andreleasing said charge into said combustion chamber from theother end of said piston.

19. In an internal combustion engine, the combination of a cylinder, apiston therein,

